A box contains $15$ tickets numbered $1, 2, ....... 15$. Seven tickets are drawn at random one after the other with replacement. The probability that the greatest number on a drawn ticket is $9$, is
${\left( {\frac{9}{{10}}} \right)^6}$
${\left( {\frac{8}{{15}}} \right)^7}$
${\left( {\frac{3}{5}} \right)^7}$
None of these
Six boys and six girls sit in a row. What is the probability that the boys and girls sit alternatively
$5$ persons $A, B, C, D$ and $E$ are in queue of a shop. The probability that $A$ and $E$ always together, is
Three mangoes and three apples are in a box. If two fruits are chosen at random, the probability that one is a mango and the other is an apple is
A bag contains $4$ white, $5$ red and $6$ black balls. If two balls are drawn at random, then the probability that one of them is white is
Each of the persons $\mathrm{A}$ and $\mathrm{B}$ independently tosses three fair coins. The probability that both of them get the same number of heads is :